The invention relates to pulling cables through sections of pipe. Specifically, the invention relates to pipe bursting and replacement or pipe lining.
Pipe such as cast iron, clay or ductile metal pipe has been used for connecting homes and creating networks for utilities such as water, sewer, or gas, etc. As the pipe becomes old, it may crack or break, necessitating replacement of the pipe.
A technique know as pipe bursting is currently used as a convenient method to replace underground pipe without the need to dig up the pipe to be replaced. A pipe breaking device, commonly called an expander or a mole, is pulled or pushed through the existing pipe while it is still underground. The expander is designed to break, or burst the pipe, and at the same time to expand the broken pieces of the pipe into the surrounding soil. The expansion of the broken pipe allows the expander to pull a replacement pipe into place. Alternatively, some methods use the expander to merely pull a smaller diameter pipe into place inside the existing pipe, however, this method restricts the flow in the replaced pipe due to the smaller diameter of the replacement or liner pipe. The pipe bursting, or lining technique has typically been employed on large diameter pipe such as water or sewer main lines. Due to the size of pipe in these types of replacements, the equipment used for pulling or pushing the expander through the pipe requires a great deal of force. As a result, common equipment in the industry for pulling or pushing the expander is relatively large and expensive such as an above ground winch and pulley system. These larger scale methods also commonly require a large access pit to be excavated on at least one end of the pipe to be replaced.
More recently, the technique of pipe bursting has been employed for smaller diameter pipe such as for lateral lines. Smaller branch pipes from a large water or sewer, etc. main line are commonly referred to as lateral lines. Replacement of smaller lateral lines is typically a lower cost job than main lines, and due to the lower profit possibilities, these jobs are frequently left to smaller contractors.
A problem arises for the smaller contractors who wish to use the pipe bursting technique for lateral line replacement. The common industry equipment for drawing or pushing the expanders through the pipe is too expensive to purchase or lease relative to the smaller profits from lateral line replacement.
What is needed is a cable pulling device that is smaller, less expensive, and easy to use to be practical for lateral line replacement.
The above mentioned needs of smaller, less expensive and easier to use cable pullers are addressed by the present invention and will be understood by reading and studying the following specification.
A cable pulling device is shown. The cable pulling device includes a base unit, and a cable contacting portion. A pivot joint rotatably connects the cable contacting portion to the base unit. The cable pulling device also includes a first cable gripping device attached to the cable contacting portion, the first cable gripping device being adapted to selectively engage and release a cable. The cable pulling device also includes an actuating device adapted to cycle the cable contacting portion back and forth about the pivot joint.
Another embodiment of a cable pulling device is shown. The cable pulling device includes a base unit and a cable contacting portion. A pivot joint rotatably connects the cable contacting portion to the base unit. The cable pulling device also includes a first cable gripping device attached to the cable contacting portion, the first cable gripping device being adapted to selectively engage and release a cable. The cable pulling device also includes an actuating device adapted to cycle the cable contacting portion back and forth about the pivot joint. The cable pulling device also includes a connection surface attached to the cable pulling device, wherein the connection surface is adapted to couple to a ground working implement arm. Another embodiment of a cable pulling device is shown. The cable pulling device includes a base unit and an arcuate cable guide. The arcuate cable guide includes a cable guide groove and a friction engaging surface substantially within the cable guide groove. The cable pulling device also includes a pivot joint rotatably connecting the arcuate cable guide to the base unit and a first cable gripping device attached to the arcuate cable guide adjacent to the friction engaging surface. The cable pulling device also includes a first actuating cylinder attached to the first cable gripping device, wherein the first actuating cylinder is adapted to actuate a gripping force between the first cable gripping device and the friction engaging surface; and a second actuating cylinder adapted to cycle the arcuate cable guide back and forth about the pivot joint.
A method of pulling a cable through a section of pipe is also shown. The method includes placing a cable within a section of pipe, and placing a portion of the cable outside the section of pipe along a friction engaging surface of a cable contacting portion. The method further includes cycling the cable contacting portion through at least one cycle. A cycle includes actuating a first cable gripping device attached to the cable contacting portion, wherein a gripping force is applied to the cable in at least a portion of the friction engaging surface. The cycle also includes pivoting the cable contacting portion about a pivot joint from a first end of a range of motion to a second end of the range of motion to generate an axial pulling force in the cable. The cycle also includes releasing the first cable gripping device at the second end of the range of motion to release the gripping force on the cable, and returning the cable guide to the first end of the range of motion.